Reinhard mannesmann



(No Model.)

R. MANNBSMANN. METHOD 0I' PRUDUGING PRESSURE TENSION IN TUBULAR BODIES.

Patented Nov. 11, 1890.

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UNITED STATES PATENT OFFICE.

REINHARD MANNESMANN, OF BLIEDINGI'IAUSEN, REMSCHEID, GERMANY.

METHOD 0F PRODUCING PRESSURE-TENSION IN TUBULAR BODIES.

SPECIFICATION forming part of Letters Patent No. 440,489, dated November11, 1890).

Application filed July 2l, 1890. Serial No. 359,382. (No model.)

To all whom, it 71mg/ concern:

Be it known that I, REINHARD MANNES- MANN, a subject of the Emperor ofGermany, residing at Bliedinghausen, Remscheid, Germany, have invented anew and useful Improvement in the Method of Producing Pressure-Tensionsin Tubular Bodies, of which the following is a speciiication.

Referring to the drawings, Figure I is a longitudinal axial section ofwhat is known as a built-up gun, and Figs. II to V are diagramsillustrative of the direction of forces in the process of construction.

The invention relates to the construction of ordnance, and has for itsobject the production of guns of greater strength relat-ively tothecaliber and weight of metal than it has heretofore been possible toproduce.

The invention consists in a method or process of construction as willnow be fully described.

According to the well-.known Uchatius process, the bored bronzegun-tubes are treated in such a manner as that they will be subjected tointerior pressure and exterior traction, the two forces being appliedsimultaneously in order to obtain a homogeneous tube. This method orprocess has, however, disadvantages, in that it is diflicult touniformly apply the two forces acting in a direction at right angles toeach other upon the metal, and still more difficult to regulate or varythese forces with a View to regulate or vary the pressure and tractiontensions. My invention is designed to overcome these difficulties andaccomplish the desired ends in a manner not only more simple andeconomical, but also more efcient, and my method orprocess is based uponthe contractibility of heated metals when acted upon by a cooling agentand upon the simultaneous application of pressure.

If a heated tubular metallic body iscooled from the interior, the innerstratum in contact with the cooling agent will contract, while the outerhot stratum will retain its form. In the act of cooling and contractingof the inner stratum of metal radial forces are developed that tend toseparate the cooler from the hotter portions of the metal, as indicatedby arrows, Fig. II. As the cooling from the interior toward the exteriorproceeds, the zone at which the cooler' portions of the metal tend toseparate from the hotter portions is shifted accordingly-that is to say,this zone of tendency to separation moves outwardly as the cooling'proceeds in that direction, until iinally it vanishes at the peripherywhen the body has been uniformly cooled, as shown by arrow, Fig. III,nearly all of the tension due t0 the cooling vanishing also; but ifpressure is applied from the exterior of the tubular body and cause-d toact upon the metal simultaneously With the cooling agent the metal actedupon by pressure is made to follow up the radial tractional forceexerted in the inner cooled portions of such metal, asshown by thearrows in Fig. IV, so that these tractional forces will vanish with thezone of tendency to separation. As soon as the external compressingforce ceases to act upon the tubular body the comp ression-.tension willalso vanish or cease in that portion of said tubular body influenced bysaid force, and upon cooling the said portion will contract but little,if at all. It follows from the above that a tractional force will bedeveloped in the outer portions of the metal, while pressure-tensionswill be developed in the interior portions, as shown by arrows, Fig. V.The external pressure may be applied by any desired means-such as thehammer-or by means of rolls or hydraulic or other press. In fact, anymechanical appliance by means of which the desired pressure can beapplied may be used.

As the tubular body is cooled and contraction in the metal proceeds, thecooled and contracted portions offer a greater resistance to change ofform than the hotter outer portions of the metal, so that the said innercooled portions or strata will acquire a pressure-tension while thetubular body is being worked exteriorly and cooled interiorly, which(tension) Will increase materially with the cooling oft and consequentcontraction of the outer portions of the metal. Now, if the eX- teriorpressure is continued while the cooling from the interior proceeds, theinterior pressure-tensions and the exterior traction-tensions willincrease, thereby bringing the metal of the tubular body into moreintimate union, producing a perfectly homogeneous body capable ofresisting great internal pressures.

In Fig. I, I have illustrated a gun-.tube ot IOO that class known asbuilt-up guns;7 and composed of a plurality of concentric tubes a, b, c,d, e, and f. The phenomena that will .take place when such a tube isheated to the proper temperature, then subjected to external pressure,and simultaneously therewith cooled interiorly by the admission to thebore of asuitable cooling agent fed thereto through pipe A, Will bereadily understood from what has been said above. It is evident,therefore, that the process or method is applicable to tubular bodies,Whether such are built up of a plurality of concentric tubes or of asingle tube. If a built-up tube is heated and subjected to externalpressure and simultaneously therewith cooled interiorly,theinner tubesWill be subjected to pressure aud the outer ones to traction. When sucha tube is subjected to high internal pressure, the interior diam eterWill slightly increase, and When said' internal pressure has reached agiven degree the pressure-tension in the inner tubes Will be convertedinto traction-tension, so that all of the tubes will then be subjected'to traction-tension.

From the description of the method or process it will readily be seenthat the tensions inthe different strata of the tubular body may bedetermined, more especially the proportional radial pressure tensionexerted from the interior of the tubular body and its transition intotraction-tension, so that according'to the nature and degree of theinternal pressure to which the tubular body may finally be subjected thezone of no tension may be removed farther from or brought nearer to theinner surfaces of such body on the one hand, and on the other it will bepossible to impart to the metal adjacent to the interior 'stratum asuitable pressure-tension. This may be effected by simply regulating thedegree to which the tubular body is heated and thev degree to whichit iscooled. interiorly during'themanipulation of such body.

Any Suitable cooling agent may be em ployed, either solid, liquid, orgaseous, and I would have it understood that I do not limit myself toany particular cooling agent or to the means of applying the same; nordo I desire t'o limit myself to any particular means for applying theexternal pressure, which, as'

above stated, may be of any suitable character.

Finally, it will be readily understood that the process or method is notonly applicable to the construction of ordnance, but also to theconstruction of the tubes or barrels of small {ire-arms, and to theconstruction in general of all cylindrical hollow bodies as aresubjected to great internal pressures in practical use-such, forinstance, as the cylinders of hydraulic presses, and so on.

Having thus described myinvention, What I claim, and desire to secure byLetters Patent, 1s-

l. The herein-described improvement in the construction of tubularbodies, which consists in producing a shrinkage of the interior Walls ofthe tubular body and in causing the remaining metal to follow up suchshrinkage by applying external pressure for the purposes specified.

2. The herein-described improvement in the construction of tubularbodies, which consists in introducing a cooling agent into the tubularbody while in a heated conditionand simultaneously therewith subjectingthe said body to external pressure. v

3. The herein-described improvement in the construction of tubularbodies, which consists in subjecting a bundle of concentric tubes toexternal pressure while in a heated condition and in simultaneouslycooling said bundle of tubes from the interior.

4. The herein-described improvement in the construction of gun tubes andbarrels, which consists in forming a bundle by-telescoping a pluralityof tubes havingvcomparatively thin walls, in uniting the tubes bysubjecting t-he bundle to external pressure While in a heated condition,and in simultaneously cooling the said bundle by introducing'a coolingagent into the inner tube thereof. j I

In Witness whereof I have hereunto set my hand in the presence of twoattesting Witnesses.

` REINHARD MANNESMANN. Witnesses: n

GEORGE LOUBIER, ADoLt` DEMELINS.

